introduction of Intel 8080 2MHz microprocessor
Intel 8080 microprocessor is a successor to the Intel 8008 CPU. The 8080 was designed by Federico Faggin and Masatoshi Shima. Stan Mazor contributed to chip design. The work on 8080 microprocessor was started at the end of 1972, and the CPU was released in April of 1974. Original version of the 8080 had a flow - it could only drive low-power TTL devices. After the flow was discovered Intel released updated version of the CPU - 8080A, which could drive standard TTL devices.
The Intel 8080/8080A was not object-code compatible with the 8008, but it was source-code compatible with it. The 8080 CPU had the same interrupt processing logic as the 8008, which made porting of old applications easier. Maximum memory size on the Intel 8080 was increased from 16 KB to 64 KB. The number of I/O ports was increased to 256. In addition to all 8008 instructions and addressing modes the 8080 processor included many new instructions and direct addressing mode. The 8080 also included new Stack Pointer (SP) register. The SP was used to specify position of external stack in CPU memory, and the stack could grow as large as the size of memory. Thus, the CPU was no longer limited to 7-level internal stack, like the 8008 did.
The Intel 8080 microprocessor was very popular and was second-sourced by many manufacturers. Clones of the 8080 processor were made in USSR, Poland, CSSR, Hungary and Romania.
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